"Most scripts written by system administrators to run UNIX systems involve sed. You can't really administer the system adequately if you can't read system scripts, so just learning how to read sed will help you understand vital system scripts like rc.

"Since understanding system scripts is so important for system administrators, you would think that there would be more books on sed, but there are only bits and pieces in a few books. [T]here has never been a book that gave sed more than a few pages. As for that, how many books have you ever seen on awk aside from a small volume called the AWK Programming Language by Aho, Kernighan and Weinberger? System administrators frequently use awk. Since awk is a pattern-matching language, it is perfect for applications requiring filtering with programming constructs.

"So where can system administrators turn to find the information they need on important topics like awk and sed?

"Once again O'Reilly and Associates shows its senstitivity to the needs of UNIX system administrators with an excellent new book authored by Dale Dougherty entitled sed & awk. I have read many UNIX and C books that not only have been easy to put down, it required a lot of discipline to pick them up and continue plowing through them, but I found sed & awk fascinating and compelling. I have been using and teaching both sed and awk for a decade and never knew the full extent of their powers until I read this fine Nutshell book.

"Dougherty takes a spiral approach to teaching, laying down a solid foundation of background material before hitting the reader with sed and
awk. Since awk and sed are dependent on regular expressions, Dougherty starts off with a comprehensive review of regular expressions. Then he goes into the editors (ed, vi, and ex), for there is no sense in even studying sed and awk until you have a firm grip on the editors. He shows you how to use regular expressions in editors to accomplish useful work, such as doing searches and replaces. Only after spending at least 50 pages on editors and regular expressions does Dougherty tackle sed and awk.

"Once into sed, the fun really starts, for what Dougherty does with sed is amazing. He takes formatted manual pages and reverse-engineers them back into troff-ready text with multiple-line sed programs. In day-to-day use, system administrators don't usually use sed in lengthy programs, and seeing them in this fashion alters your thinking and forces you to treat sed with increased respect.

"I won't spoil your enjoyment of this remarkable book by telling you more except to say that it gets better from there. Suffice to say that awk is covered with equal thoroughness.

"Dougherty obviously enjoys what he's writing about, and his excitement about the subject draws you in. His master of the subject makes you feel comfortable with even the most complex sed scripts, and as you read the explanations, you feel confident enough to try your hand at them, too. The sed and awk utilities have been extended through the years, such as a new awk called nawk, and this book even covers those extensions.

"sed & awk is a must for UNIX system programmers and administrators, and even general UNIX readers will benefit. I have over a hundred UNIX and C books in my personal library at home, but only a dozen are duplicated on the shelf where I work. This one just became number twelve." --Root Journal, January/February 1991